Ligases (EC 6) Ligases are enzymes classified under EC 6 that catalyze the joining of two molecules by forming new covalent bonds, often accompanied by the hydrolysis of a high-energy molecule like ATP or GTP. These enzymes are crucial in a variety of biological processes, including DNA replication, repair, and biosynthesis of macromolecules such as … Read more
Isomerases (EC 5) Isomerases are enzymes classified under EC 5 that catalyze the rearrangement of atoms within a molecule, converting it into its isomeric form. Isomerases play crucial roles in many metabolic pathways by facilitating the conversion of molecules into different structural or stereoisomers without changing the molecular formula. These enzymes are essential for maintaining … Read more
Lyases (EC 4) Lyases are enzymes classified under EC 4 that catalyze non-hydrolytic reactions in which a functional group is removed from a substrate or added to a substrate without the use of water or oxidation. Unlike hydrolases, which break bonds by using water, lyases break or form bonds by mechanisms that do not involve … Read more
Hydrolases (EC 3) Hydrolases are enzymes classified under EC 3 that catalyze the hydrolysis of chemical bonds. Hydrolysis is a reaction in which a water molecule is used to break a bond in a substrate, resulting in the formation of two products. Hydrolases are involved in many essential biological processes, including digestion, cellular metabolism, and … Read more
Transferases (EC 2) Transferases are enzymes classified under EC 2 that catalyze the transfer of functional groups (such as methyl, acetyl, amino, phosphate, or sugar groups) from one molecule (the donor) to another molecule (the acceptor). These enzymes play crucial roles in various metabolic processes, including protein modification, signal transduction, and the regulation of cellular … Read more
Oxidoreductases Oxidoreductases (EC 1) are a class of enzymes that catalyze oxidation-reduction reactions (redox reactions). In these reactions, electrons are transferred between molecules, which may involve the transfer of hydrogen atoms or the addition or removal of electrons. Oxidoreductases play crucial roles in various biochemical processes, including metabolism, cellular respiration, and the detoxification of harmful … Read more
Classification of Enzymes (EC Number System) Enzymes are classified based on the types of reactions they catalyze. The EC (Enzyme Commission) Number System is a widely accepted method of classifying enzymes. This system was established by the International Union of Biochemistry and Molecular Biology (IUBMB) to provide a standardized way of naming and categorizing enzymes … Read more
Holoenzymes and Prosthetic Groups Enzymes are biological catalysts that often require additional non-protein components to be fully functional. These components can include holoenzymes and prosthetic groups, which work together with the enzyme’s protein component (the apoenzyme) to enable proper catalytic activity. Both are essential for the enzyme to perform its biological functions efficiently. 1. Holoenzymes … Read more
Apoenzymes and Cofactors Enzymes are biological catalysts that are often made up of two components: an apoenzyme and a cofactor. Both are necessary for the enzyme to be fully functional and to carry out its catalytic activity. The apoenzyme provides the protein structure, while the cofactor is typically a non-protein component that assists in the … Read more
Active Site and Substrate Binding The active site is a specific region of an enzyme where substrate molecules bind and undergo a chemical reaction. The interaction between the enzyme’s active site and its substrate is fundamental to enzyme catalysis, as it determines the enzyme’s specificity, efficiency, and the overall rate of the reaction. Understanding how … Read more